In general, a pipe is widely used for transporting a fluid such as water or oil or a gas. The pipe is manufactured by a uniform standard (length) due to limitations on transporting and handling to be sold.
Therefore, when a section longer than the standard length of the pipe or a curved section is constructed, a pipe connecting device must be used or the pipe must be welded to be connected.
There are various pipe connecting devices for connecting the pipe used for a piping. In particular, a pipe connecting device in which a grip ring is used to prevent a pipe inserted into a connector from escaping is widely used for pipe fitting due to easiness of a connecting work.
FIG. 1 is an exploded perspective view illustrating a conventional pipe connecting method. FIG. 2 is a vertical sectional view of FIG. 1. In the conventional pipe connecting method, as illustrated in FIGS. 1 and 2, a pipe 3 is inserted into a nut 2 including a female screw 2a and, in a state where an O-ring 6, a washer 5, and grip ring 4 are sequentially installed in the pipe 3, the nut 2 is screw combined with a male screw 1a of a piping 1.
Therefore, in a state where the grip ring 4 installed in the pipe 3 is kept close to a first stopper 1b of the piping 1, when a protrusion 2b of the nut 2 compresses the O-ring 6, since external circumferences of the O-ring 6 and the pipe 3 are sealed up to maintain air tightness and the washer 5 pushes the grip ring 4, a grip 4a of the grip ring 4 presses the pipe 3 to perform clamping so that the pipe 3 is not separated from the pipe connecting apparatus. Such an operation is performed until the nut 2 is completely screw tightened to the piping 1.
However, in the conventional pipe connecting method, there are limitations on the grip ring 4 inserted into the pipe 3 maintaining a predetermined insertion (installation) depth. Therefore, when the insertion depth of the grip ring 4 is small, the pipe 3 escapes from the pipe connecting device and, to the contrary, when the insertion depth of the grip ring 4 is large, the nut is tightened in a state where a leading end of the pipe 3 is kept close to a second stopper 1c of the piping when the nut 2 is screw combined with the piping 1 so that the grip ring 4 is damaged, the external circumference of the pipe 3 is scratched by the grip 4a, or a bottle neck phenomenon of the pipe is caused by excessive compression of the O-ring 6 to lead the pipe to escape from the pipe connecting device.
Furthermore, in the conventional pipe connecting method, when a worker makes a mistake or has poor workmanship, an assembly sequence of parts is changed so that the pipe 3 is separated from the pipe connecting device.
Due to the above-described problem, the pipe connector assembly illustrated in FIG. 3 is developed and used.
FIG. 3 is a vertical sectional view illustrating a conventional pipe connector assembly. FIG. 4 is a vertical sectional view illustrating that a pipe is inserted into an insert hole of parts in a state where a cover is separated from a housing. A first stopper 7a is formed in a housing 7 formed of synthetic resin so that the grip ring 4, the washer 5, and the O-ring 6 are assembled in the order and positions of the grip ring 4, the washer 5, and the O-ring 6 are determined. A second stopper 7b for restricting the insertion depth of the pipe 3 that passes through the grip ring 4, the washer 5, and the O-ring 6 is formed under the first stopper 7a. The grip ring 4, the washer 5, and the O-ring 6 assembled with the housing 7 are protected by a cover 8.
Therefore, in order to perform a connecting work of the pipe, when over 8 is removed from the housing 7 and the pipe 3 to be constructed is pushed to the insert hole of the parts, since the leading end of the pipe 3 is locked on the second stopper 7b and the grip ring 4, the washer 5, and the O-ring 6 are sequentially positioned on the external circumference of the pipe 3, the connecting work of the piping may be performed.